Implement memmap.Mappable and memmap.File for vfioFd.

PiperOrigin-RevId: 615472230

Author: milantracy

pkg/sentry/devices/tpuproxy/BUILD

@@ -12,6 +12,7 @@ go_library(
         "tpu.go",
         "tpu_mmap.go",
         "vfio.go",
+        "vfio_mmap.go",
     ],
     visibility = [
         "//pkg/sentry:internal",

pkg/sentry/devices/tpuproxy/device.go

@@ -117,6 +117,7 @@ func (dev *vfioDevice) Open(ctx context.Context, mnt *vfs.Mount, d *vfs.Dentry,
 		unix.Close(hostFd)
 		return nil, err
 	}
+	fd.memmapFile.fd = fd
 	return &fd.vfsfd, nil
 }
 

pkg/sentry/devices/tpuproxy/tpu.go

@@ -40,7 +40,7 @@ type tpuFD struct {
 	hostFD     int32
 	device     *tpuDevice
 	queue      waiter.Queue
-	memmapFile tpuFdMemmapFile
+	memmapFile tpuFDMemmapFile
 }
 
 // Release implements vfs.FileDescriptionImpl.Release.

pkg/sentry/devices/tpuproxy/tpu_mmap.go

@@ -60,25 +60,25 @@ func (fd *tpuFD) InvalidateUnsavable(ctx context.Context) error {
 	return nil
 }
 
-type tpuFdMemmapFile struct {
+type tpuFDMemmapFile struct {
 	fd *tpuFD
 }
 
 // IncRef implements memmap.File.IncRef.
-func (mf *tpuFdMemmapFile) IncRef(memmap.FileRange, uint32) {
+func (mf *tpuFDMemmapFile) IncRef(memmap.FileRange, uint32) {
 }
 
 // DecRef implements memmap.File.DecRef.
-func (mf *tpuFdMemmapFile) DecRef(fr memmap.FileRange) {
+func (mf *tpuFDMemmapFile) DecRef(fr memmap.FileRange) {
 }
 
 // MapInternal implements memmap.File.MapInternal.
-func (mf *tpuFdMemmapFile) MapInternal(fr memmap.FileRange, at hostarch.AccessType) (safemem.BlockSeq, error) {
+func (mf *tpuFDMemmapFile) MapInternal(fr memmap.FileRange, at hostarch.AccessType) (safemem.BlockSeq, error) {
 	log.Traceback("tpuproxy: rejecting tpuFdMemmapFile.MapInternal")
 	return safemem.BlockSeq{}, linuxerr.EINVAL
 }
 
 // FD implements memmap.File.FD.
-func (mf *tpuFdMemmapFile) FD() int {
+func (mf *tpuFDMemmapFile) FD() int {
 	return int(mf.fd.hostFD)
 }

pkg/sentry/devices/tpuproxy/vfio.go

@@ -34,9 +34,10 @@ type vfioFd struct {
 	vfs.DentryMetadataFileDescriptionImpl
 	vfs.NoLockFD
 
-	hostFd int32
-	device *vfioDevice
-	queue  waiter.Queue
+	hostFd     int32
+	device     *vfioDevice
+	queue      waiter.Queue
+	memmapFile vfioFDMemmapFile
 }
 
 // Release implements vfs.FileDescriptionImpl.Release.

pkg/sentry/devices/tpuproxy/vfio_mmap.go

@@ -0,0 +1,84 @@
+// Copyright 2024 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package tpuproxy
+
+import (
+	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/errors/linuxerr"
+	"gvisor.dev/gvisor/pkg/hostarch"
+	"gvisor.dev/gvisor/pkg/log"
+	"gvisor.dev/gvisor/pkg/safemem"
+	"gvisor.dev/gvisor/pkg/sentry/memmap"
+	"gvisor.dev/gvisor/pkg/sentry/vfs"
+)
+
+// ConfigureMMap implements vfs.FileDescriptionImpl.ConfigureMMap.
+func (fd *vfioFd) ConfigureMMap(ctx context.Context, opts *memmap.MMapOpts) error {
+	return vfs.GenericConfigureMMap(&fd.vfsfd, fd, opts)
+}
+
+// AddMapping implements memmap.Mappable.AddMapping.
+func (fd *vfioFd) AddMapping(ctx context.Context, ms memmap.MappingSpace, ar hostarch.AddrRange, offset uint64, writable bool) error {
+	return nil
+}
+
+// RemoveMapping implements memmap.Mappable.RemoveMapping.
+func (fd *vfioFd) RemoveMapping(ctx context.Context, ms memmap.MappingSpace, ar hostarch.AddrRange, offset uint64, writable bool) {
+}
+
+// CopyMapping implements memmap.Mappable.CopyMapping.
+func (fd *vfioFd) CopyMapping(ctx context.Context, ms memmap.MappingSpace, srcAR, dstAR hostarch.AddrRange, offset uint64, writable bool) error {
+	return nil
+}
+
+// Translate implements memmap.Mappable.Translate.
+func (fd *vfioFd) Translate(ctx context.Context, required, optional memmap.MappableRange, at hostarch.AccessType) ([]memmap.Translation, error) {
+	return []memmap.Translation{
+		{
+			Source: optional,
+			File:   &fd.memmapFile,
+			Offset: optional.Start,
+			Perms:  at,
+		},
+	}, nil
+}
+
+// InvalidateUnsavable implements memmap.Mappable.InvalidateUnsavable.
+func (fd *vfioFd) InvalidateUnsavable(ctx context.Context) error {
+	return nil
+}
+
+type vfioFDMemmapFile struct {
+	fd *vfioFd
+}
+
+// IncRef implements memmap.File.IncRef.
+func (mf *vfioFDMemmapFile) IncRef(memmap.FileRange, uint32) {
+}
+
+// DecRef implements memmap.File.DecRef.
+func (mf *vfioFDMemmapFile) DecRef(fr memmap.FileRange) {
+}
+
+// MapInternal implements memmap.File.MapInternal.
+func (mf *vfioFDMemmapFile) MapInternal(fr memmap.FileRange, at hostarch.AccessType) (safemem.BlockSeq, error) {
+	log.Traceback("tpuproxy: rejecting vfioFdMemmapFile.MapInternal")
+	return safemem.BlockSeq{}, linuxerr.EINVAL
+}
+
+// FD implements memmap.File.FD.
+func (mf *vfioFDMemmapFile) FD() int {
+	return int(mf.fd.hostFd)
+}